Zenon Environmental Inc.

Ake A Deutschmann

Henry Behmann

Anthony A Tonelli

Mailvaganam Mahendran

Wayne Jerald Henshaw

Susan L Wesno

Bradley M Smith

Pierre Lucien Cote

Steven Kristian Pedersen

Kenneth Paul Goodboy

Carlos F Rodrigues

Eric Harrison

Frederick J Daly

Martin J Hauschild

A filtration device is provided for withdrawing permeate essentially continuously from a multicomponent aqueous substrate containing growing microorganisms in a reservoir. A vertical skein of fiber is scrubbed with coarse bubbles which emanate from a conversion baffle positioned under the skein. The substrate is aerated with fine bubbles in a size range small enough to transfer oxygen to the substrate efficiently. The baffle traps the fine bubbles and converts them to coarse bubbles which are effective to scrub the fibers. In the most preferred embodiment, the finished headers of the skein are derived from composite headers comprising a fixing lamina of resin in which the fibers are potted near their terminal ends, and a fugitive lamina of fugitive powdery material in which the terminal ends of the fibers are potted. The fugitive lamina is removed, preferably by dissolving the powder, e.g. finely divided common salt in water.

Potted header for hollow fiber membranes

An adaptive control method for producing high purity water, the method having the ability to produce high purity water on a continuous basis having a resistivity in the range of 0.8 to 4 megohm-cm. The method comprises the steps of providing a feedwater to be purified and providing a first reverse osmosis unit having a first high pressure side and a first low pressure side and having a first permeate produced at the first low pressure side. The pH of the feedwater to be introduced to the high pressure of the first reverse osmosis unit is monitored before introducing the feedwater to the high pressure side of the first reverse osmosis unit. Also, the feedwater is maintained in a temperature range of 45.degree. to 80.degree. F. A second reverse osmosis unit is provided having a second high pressure side and a second low pressure side for producing high purity product water. The first permeate from the first reverse osmosis unit is passed to the high pressure side of the second reverse osmosis unit and the resistance of the product water produced at the second low pressure side of the second reverse osmosis unit is measured to provide a resistance measurement. The resistance measurement is relayed to a programmable logic controller where it is compared to previous resistance measurements to provide a comparison. In response to the comparison, the pH of the feed water is either maintained or is changed upwardly or downwardly to produce high purity water having the desired resistivity.

High resistivity water production with controlled water temperatures

A method for producing high purity product water using a three pass reverse osmosis system.

High purity water using triple pass reverse osmosis (TPRO)

A method of purifying impure water to provide drinking water using an apparatus, the method comprising the steps of providing a microfiltration unit, a reverse osmosis unit and a CIP (clean-in-place) tank containing retentate interconnected to permit backflushing the microfiltration filter with retentate and continued or uninterrupted operation of the reverse osmosis unit by directing retentate thereto.

Portable reverse osmosis unit for producing drinking water

Potted header for hollow fiber membranes and method for making it

Method for producing high purity water using triple pass reverse osmosis

Baffle for conversion of fine bubbles to coarse while filtering with a

A method and cleaning system is disclosed for cleaning the outer surface of a fouled microfiltration (MF) or ultrafiltration (UF) semipermeable hollow fiber membrane after its initial stable transmembrane flux has been decreased to an unacceptably low level. The method is specifically applicable to any fiber used to withdraw purified water from dirty water, particularly water containing organic matter including beneficial bacteria and/or undesirable inorganic salts, where the viability of the bacteria population is to be maintained. The membrane is cleaned by flowing a cleaning fluid, preferably a biocidal oxidative electrolyte having an oxidizing anion and an associated cation through the clean, permeate-side of the membrane, at low pressure no more than the bubble pressure breakthrough, usually &lt;300 kPa (30 psig) for a MF or UF fiber. Such low pressure is sufficient to diffuse the electrolyte through both, the pores of the membrane and a fouling film which typically includes a biofilm accumulated on the fibers' outer surface, but not enough electrolyte flows through the membrane to kill numerically more than 20% of the living bacteria in the dirty water. This limitation can be met only if the cleaning period is brief. This period is only long enough to oxidize organic matter within the pores and kill essentially all bacteria in the biofilm. Preferably less than 5% of the bacteria population is decimated. As diffusion takes place, pores are again opened, both in the wall of the fiber and through the biofilm, and when the fibers are returned to normal operation, the restored flux is equal to at least 70% of the initial stable flux.

In situ cleaning system for fouled membranes

A frameless array unconfined in a modular shell, proves to be a surprisingly effective membrane device for withdrawing permeate from a substrate, the flux through the membranes reaching an essentially constant relatively high value because of the critical deployment of fibers of the array as a skein, arching in a buoyantly swayable generally parabolic configuration within the substrate, above at least one of the array's headers in which the terminal end portions of the fibers are potted. The length of each fiber must be greater than the direct center-to-center distance between the array's pair of headers. For use in a large reservoir, an assembly of the array and a gas distributor means has fibers preferably &gt;0.5 meter long, which together provide a surface area &gt;10 m.sup.2. The terminal end portions of fibers in each header are substantially free from fiber-to-fiber contact. When used in a tank from which the permeate is withdrawn at a location low enough to overcome the transmembrane pressure differential of the fibers, the permeate is withdrawn under a vacuum induced by gravity. To increase flux, a pump may be used which provides a suction less than 75 cm of Hg. When used in combination with a gas-distribution manifold disposed beneath the skein so as to flow bubbles through it, the surfaces of the fibers are surprisingly resistant to being fouled by build-up of deposits of inanimate particles or microorganisms in the substrate. Membranes with high transmembrane pressure differential may be used, if desired, and permeate removed with a vacuum pump.

Frameless array of hollow fiber membranes and method of maintaining

Growing community of inventors

Burlington, Canada

Ake A Deutschmann